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How To Caramelize Onions – Tips for Success Every Time

If you don’t know how to caramelize onions, you’re in the right place. Below you’re going to learn how to make easy caramelized onions and get cooking tips to avoid common mistakes.

There is nothing quite like the taste of caramelized onions. Raw onions have a strong bite, but caramelizing them releases their sugars and gives them a sweet, mellow flavor.

Perfect caramelized onions take time to make, but the end product is worth the wait! Being patient is a crucial step in the process of caramelizing onions, and one that you can’t rush.  

Two of the most common mistakes when making caramelized onions are trying to cook the onions too quickly and removing them from the pan too soon.

Keep reading for an easy caramelized onions recipe and tips for success. If you are a visual learner, you can watch this YouTube video tutorial showing how to make caramelized onions.

A collage of six different close up shots of caramelized onions at different points in the cooking process, each one with a different caramelized onion color, with a text overlay that reads how to caramelize onions video tutorial and printable instructions.

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Easy caramelized onion ingredients

The first step is to gather your tools and ingredients. You’ll need the following items:

How to caramelize onions

To make these easy caramelized onions, prep your onions by cutting them in half, through the root end. Then cut off the roots and the tops of your onion and peel them. 

Cut your onion into slices that are 1/8 inch to 1/4 inch thick. Be sure to slice with the grain of the onion (pole to pole) and not against the grain. Slicing against the grain yields weaker slices that could turn mushy.

Put your cast iron pan over a medium heat and let it come to temperature. Add 3 tablespoons of canola oil (or any other high smoke point, neutral oil) and your onions.

Press the onions down in the pan with your spatula. Stir them every 3-5 minutes, making sure to press them back down into your pan with the back of your spatula.

Once they are soft and translucent (around the 17 minute mark), lower your heat slightly. Your heat should be somewhere between medium and medium low – you still want to be able to hear the onions sizzling. They should look like the photo below:

A process shot showing how to caramelize onions in a cast iron pan, where the pan is on the stove, and caramelized onions are just starting to turn translucent, yielding a yellow caramelized onion color.

Continue cooking, stirring and turning the onions every 3-5 minutes. Once the onions start browning and caramelizing, scrape up any fond (bits that are stuck to the pan) and stir it into the onions.

If you notice the onions or the fond is turning black instead of brown, your heat is too high. This is a sign to reduce your heat.

As your onions begin to caramelize, you’ll need to stir them more often. Once they really start changing color, you’ll need to stir them every 1-2 minutes (always pressing them back into the pan when you’re done).

Once your onions are a deep brown color (around 70 minutes), add a splash of balsamic vinegar to deglaze the pan and stir.

The final step is seasoning your onions with salt. It’s better to do this at the end of the cooking process, because you can season them to your taste. 

Using a cast iron handle cover (because the handle will be very hot), tilt the pan at an angle so some of the oil can drain out of the onions. Push the onions towards the handle, and let the oil drain away from them. This should only take a minute or so.

Remove and enjoy! You can get printable instructions for how to caramelize onions in the project card at the bottom of the page.

There’s so many different ways to use caramelized onions; if you’d like some ideas you can check out these recipes using caramelized onions.

A photo collage showing an how to caramelize onions with two images of whole onions, a process shot of a teal spatula stirring caramelized onions in a cast iron pan, and a final picture of the end result of the easy caramelized onions recipe.

“Why won’t my onions caramelize?” and other FAQs:

If you’ve tried making caramelized onion recipes in the past without much luck, you’re not alone! There are a few simple mistakes that many people make when caramelizing onions, but fortunately they can all be avoided.

Below are some commonly asked questions and tips for caramelizing onions.

How long does it take to caramelize onions?

There are several variables that effect how long it takes to caramelize onions including the amount of onions you’re using, the size of your pan, how high the heat is when you’re cooking and how thinly or thickly you slice your onions.

If you follow the instructions in this easy caramelized onions recipe it will take you about an 60-70 minutes. The most flavorful caramelized onions take time, and are worth the wait!

What onions are best for caramelizing?

You can actually caramelize any type of onion! Yellow onions and sweet onions are the most commonly caramelized, but you can also caramelize red onions, white onions and shallotsA photo showing four different varieties of onions, including a white onion, red onion, yellow onion and shallot, all of which can be used as types of onions for caramelizing onions.

What is the best oil for caramelizing onions?

Since you’ll be cooking over a high heat, you’ll want to use a high smoke point oil.

It’s also a good idea to use an oil with a neutral taste, so the caramelized onions can shine. Some good options for neutral oils with a high smoke point are avocado oil, canola oil, corn oil, grapeseed oil and safflower oil. 

Stay away from oils with a lower smoke point (like olive oil) and oils with strong flavor (like sesame oil).

If you’re going to be using butter instead (or a mix of butter and oil), make sure to use clarified butter or ghee. Regular butter has a lower smoke point and will burn, whereas clarified butter and ghee will be able to stand up to the heat.

Can you explain how to cut onions for caramelizing?

You want to slice your onions so they are between an eighth of an inch thick to a quarter of an inch thick. Make sure to slice your onions with the grain, from root to top (pole to pole). 

Cut evenly sized slices of onions. Having even slices encourages even caramelization. Make sure not to slice them too thinly or they’ll stick to the bottom of your pan and burn easily. 

Step-by-step instructions for the best way to cut onions for caramelizing, depicted in four images starting with a photo slicing the onion in half through the root, then showing the onion cut in half with the root and top cut off, then showing it being sliced into slices that are 1/4 inch to 1/8 inch thick, and finally showing rotating the onion at the mid-point to finish slicing it.

What does it mean to caramelize onions?

When onions are heated to a temperature over 300°F (149°C) they begin to caramelize. This caramelization occurs because that high heat is breaking down the natural sugars in the onions.

When the amino acids in the onions are exposed to these sugars, they undergo what is called the Maillard reaction, which causes the characteristic brown color of caramelized onions.

What color should caramelized onions be?

The color of caramelized onions is one of the most clear indicators that you’ve cooked them long enough. You want your caramelized onion color to be dark brown and translucent.

Don’t pull your onions off the heat too soon. It take about 40 minutes for the onions to start caramelizing, but up to 70 minutes be be fully caramelized.

If you remove them early, you’ll miss the depth of flavor they develop as they continue to caramelize.

A close up shot of caramelized onions in a white bowl, with the color of caramelized onions being a deep brown, with some slightly translucent slices.

What do caramelized onions taste like?

Caramelized onions have a mellow, sweet and savory taste, which is a contrast to the sharp bite of raw onions. The natural sweetness of caramelized onions is similar to that of roasted garlic.

When are caramelized onions done?

Caramelized onions are done when they have a deep, dark brown color, are soft, and have a rich sweetness to them. It normally takes about 60-70 minutes to cook caramelized onions over a medium heat to yield this result.

If your caramelized onions are black, you’ve burned them. If they are a light caramel color, they haven’t been cooked long enough.

A graphic showing how to caramelize onions with eight different photos of the caramelized onions in a cast iron pan at different times during the recipe with time stamps, and a text overlay reading how long does it take to caramelize onions.

Why are my caramelized onions mushy?

There are several reasons your caramelized onions may be mushy. If you added baking soda (as some recipes suggest) to speed up the cooking time, this could be the reason they’re mushy.

They can also become mushy from overcooking or improper slicing.

When slicing your onion, want to make slices from pole to pole (root to top), following the grain of the onion. If you slice onions against the grain (like you would to make onion rings) they’re more likely to be mushy.

Can you explain how to store caramelized onions?

They’re so delicious I doubt they’ll last very long in your home. If you make a large batch of these easy caramelized onions, you can put them in the freezer in silicone trays for up to 3 months. You can also store them in the fridge for about a week.

Why won’t my onions caramelize?

If your onions aren’t caramelizing, you might be stirring too often. Caramelized onions need to make contact with the bottom of the pan to caramelize and brown. If you are stirring them constantly they won’t be able to do that.

In the beginning you can stir them every 3-5 minutes. When they start caramelizing, they’ll cook more quickly, so keep a close eye on them and stir them every minute or two.

Make sure to press your onions back down into the pan with your spatula after you finish stirring so they make contact with the surface of the pan.

What are some other tips for caramelized onions?

Don’t try to shorten your cooking time by turning the heat up high! Doing this will burn them, every single time.

Start by cooking your onions over medium heat. Once they become translucent, turn down the heat between medium low and medium. This is the best temperature for perfect caramelized onions.

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Learning how to caramelize onions is an essential cooking tip. Onions cooked this way add loads of flavor to so many dishes.

Yield: 1 cup of perfect caramelized onions

How To Caramelize Onions - Tips for Success Every Time

A photo collage showing an how to caramelize onions with two images of whole onions, a process shot of a teal spatula stirring caramelized onions in a cast iron pan, and a final picture of the end result of the easy caramelized onions recipe.

If you want to learn how to caramelize onions, and are looking for the best caramelized onions recipe that will give you success every time, you've found it!

They key to this recipe is patience. It takes about an hour to make this caramelized onion recipe, but they're definitely worth the wait.

Prep Time 5 minutes
Cook Time 1 hour 10 minutes
Total Time 1 hour 15 minutes

Ingredients

  • 3 Sweet onions
  • 3 Tablespoons canola oil
  • Salt, to taste
  • Splash of balsamic vinegar

Instructions

  1. Slice your onions in half, through the root end.
  2. Cut off the roots and the tops of your onion halves.
  3. Peel your onions.
  4. Cut your onions into slices that are 1/8 inch to 1/4 inch thick. Make sure to slice with the grain of the onion (pole to pole) and not against the grain. Slicing against the grain yields weaker slices that could turn mushy.Step-by-step instructions for the best way to cut onions for caramelizing, depicted in four images starting with a photo slicing the onion in half through the root, then showing the onion cut in half with the root and top cut off, then showing it being sliced into slices that are 1/4 inch to 1/8 inch thick, and finally showing rotating the onion at the mid-point to finish slicing it.
  5. Put your cast iron pan over a medium heat and give it enough time to come up to temperature. 
  6. Add 3 tablespoons of canola oil (or any other high smoke point, neutral oil).
  7. Add all of your onions.
  8. Press the onions in the pan with your spatula. 
  9. Stir them every 3-5 minutes, making sure to press them back down into your pan each time you stir them.
  10. Once they are soft and translucent (around the 17 minute mark), lower your heat to somewhere between medium and medium low - you still want to be able to hear the onions sizzling. They should look like the photo below:A process shot showing how to caramelize onions in a cast iron pan, where the pan is on the stove, and caramelized onions are just starting to turn translucent, yielding a yellow caramelized onion color.
  11. Continue stirring and turning the onions every 3-5 minutes. 
  12. Once the onions start browning and caramelizing, scrape up any fond (bits that are stuck to the pan) and stir it into the onions.
  13. As your onions begin to caramelize, and start changing color, you'll need to stir them more often, roughly every 1-2 minutes (always pressing them back into the pan when you're done).
  14. Once your onions are a deep brown color (around 70 minutes), add a splash of balsamic vinegar to deglaze the pan and stir. 
  15. Season to taste with salt.
  16. Put a cast iron handle cover on your (very hot) handle and tilt the pan at an angle.
  17. Push the onions towards the handle, so the oil can drain away from them. This should only take a minute or so.
  18. Remove and enjoy! A close up shot of caramelized onions in a white bowl, with the color of caramelized onions being a deep brown, with some slightly translucent slices.

Notes

  • A note on heat: If you notice the onions or the fond is turning black instead of brown, your heat is too high. This is a sign to reduce your heat.
  • A note on stirring: As your onions begin to caramelize, you'll need to stir them more often. In the beginning you’ll need to stir every 3-5 minutes, but as they start to caramelize you’ll need to stir every 1-2 minutes so they don’t burn.
  • A note on patience: It takes 60-70 minutes to make this caramelized onion recipe. Don’t try to rush it by turning up your heat or you’ll end up burning the onions! A graphic showing how to caramelize onions with eight different photos of the caramelized onions in a cast iron pan at different times during the recipe with time stamps, and a text overlay reading how long does it take to caramelize onions.

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Nutrition Information:

Yield:

1

Serving Size:

1

Amount Per Serving: Calories: 695Total Fat: 42gSaturated Fat: 3gTrans Fat: 0gUnsaturated Fat: 38gCholesterol: 0mgSodium: 664mgCarbohydrates: 78gFiber: 9gSugar: 52gProtein: 8g

Nutritional information is approximate due to natural variation in ingredients and the cook-at-home nature of our meals.

Admin note: This post showing an easy way to caramelize onions originally appeared on the blog in July of 2017. It has been updated with all new photos and a video tutorial explaining how to make caramelized onions.

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